The transferring or feeding of work pieces to various types of processing machines such as stamping machines, bending brakes, punch presses and the like, for example, by workmen involves a continual hazard to personal safety, and hand injuries are, unfortunately quite common.
To overcome this, various safety devices and protective shields have been developed for such apparatus, but they are in practice neglected by the machine operators.
Industrial safety regulations, are now becoming more specific and largely prohibit the use of such unsafe machinery. Accordingly, it is desireable to provide for some form of automatic or robotic device to simulate the hand and arm and wrist movements of a machine operator for feeding workpieces to such machines.
A variety of such robot devices have been proposed and are available. However, they suffer from various disadvantages. In particular, the programming of such robot devices usually requires a fairly sophisticated training, and is often relatively time consuming. The change over of such robot devices from one operation to another can therefore present quite a problem to management, unless a relatively large number of skilled operators are available.
It is therefore desireable to provide such robot devices with a simplified form of programming and control, which can be operated virtually by unskilled labour, or at least by labour which is no more skilled than would have performed the robot function in the first place.
In addition, such robot devices as are available on the market operate to only a relatively coarse degree of tolerance. The positional accuracy of placement of a workpiece by such a robot device is therefore somewhat imprecise, causing losses in production or variations in product quality, and in many cases jammed the press, thereby damaging the dies.
Accordingly, it is desireable therefore to increase the accuracy of and reduce the tolerances in the operation of such robot devices to the point where such wasteful results are reduced or eliminated.
In the past, the control of the operation of such robot devices has usually been effected either by means of regulation of pressure or regulation of timing of movement in any particular plane or direction, and this form of regulation has resulted in the inaccuracies referred to above, and also has in part contributed to the difficulties in programming the operation of the various functions referred to above.